The invention relates to a method for actuating headlights of a motor vehicle with a manual mode, in which the headlights can be transferred into a first illuminating state by manually actuating a selector lever in a first actuating direction. By actuating the selector lever in a second actuating direction, the headlights can be transferred into a second illuminating state. The vehicle includes an automatic mode, in which an external lighting situation is detected by sensors and evaluated by an evaluation device so that, according to the results of the evaluation, the headlights are automatically displaced into the first or into the second illuminating state. In the automatic mode, an override possibility is provided so that, independently of the results of the evaluation, the headlights can be transferred into the respective illuminating state by manually actuating the selector lever in the first or the second actuating direction.
Such a method is disclosed in German patent document DE 101 56 653 A1. The method for automatically controlling the headlights of a motor vehicle is used, in general, to decrease the negative impact on other road users by reducing the glare effect of one's own headlights, while simultaneously taking the strain off of the driver. Thereby, special sensors detect an external lighting situation, which is analyzed in a control unit or a central data processing unit. There exist a multitude of approaches for detecting the external lighting situation and for the special analysis. For example, German patent document DE 298 25 026 U1 suggests an image-forming, color-sensitive sensor, whose output images are analyzed for brightness, geometric arrangement of the light source, and the color of the light source. The results of the analysis indicate the actual properties of the detected light sources and, in particular, show whether the driver of the oncoming or leading vehicle could be possibly blinded by one's own high beam. If this is the case, an automatic shift is made to the low beam. If, in contrast, the external lighting situation is evaluated to the effect that there is no danger of blinding the other road users, one's own headlights are switched over to high beam in order to optimize the driver's own far sight.
The method disclosed in the aforementioned German patent document DE 101 56 653 A1, takes into consideration the circumstance that the driver of a motor vehicle would not like to subject himself to the automatic control of the headlights in every situation, but rather would like to be able to override the automatic adjustment as a function of the situation. In order to design the override so that it is especially easy for the driver, the same selector lever is actuated in the same way that the driver is accustomed to from the manual mode. This means that, when the high beam is automatically switched on, an actuation of the selector lever in the “low beam” direction leads to a manual switchover to the low beam, whereas, when the low beam is automatically switched on, an actuation of the selector lever in the “high beam” direction leads to a manual switchover to the high beam.
Moreover, it is known from other assistance systems, such as an automatic speed control, that the overriding of the automatic mechanism leads to the switching off of the automatic mode and to the transfer into the customary manual mode. In order to return into the automatic mode, it is necessary to actuate an additional actuating element. This requires additional components, which is associated with higher costs, and demands of the driver that he learns special manipulation steps that can vary widely from one type of vehicle to another.
The present invention provides an improved method for actuating headlights of a motor vehicle such that by suggestive actuation of familiar switching elements, the driver can always reach the optimal lighting state for his motor vehicle that is appropriate for the situation.
According to the invention, a method is provided for actuating the headlights of a motor vehicle with a manual mode, in which the headlights can be transferred into a first illuminating state by manually actuating a selector lever in a first actuating direction and by actuating the selector lever in a second actuating direction can be transferred into a second illuminating state; and with an automatic mode, in which an external lighting situation is detected by sensors and evaluated by an evaluation device so that, according to the results of the evaluation, the headlights are automatically displaced into the first or into the second illuminating state. An override possibility is provided in the automatic mode so that, independently of the results of the evaluation, the headlights can be transferred into the respective illuminating state by manually actuating the selector lever in the first or the second actuating direction. An additional override mode, which is switched on by manually actuating the selector lever in the automatic mode, is provided. In the event that the headlights are in the first illuminating state, an actuation of the selector lever in the first actuating direction causes a switching between the automatic mode and the override mode.
In contrast to the prior art, a manual override of the automatic lighting mechanism does not return the system immediately back into the manual mode. Rather, when the automatic function is overridden, the system is transferred into a special override mode, the properties of which differ from the purely manual mode, even though in the override mode no switching, controlled by automatic measures, is carried out. The present invention also provides that in an illuminating state of the headlights, an actuation of the selector lever in the manner usually used for switching on the already-existing illuminating state causes a switching between the automatic mode and the override mode. This switching can be achieved from both modes, insofar as the headlights are in the first lighting state, which is preferably the high beam state. In more precise terms, this means that, in a preferred embodiment, in the event that the high beam is switched on, a renewed actuation of the selector lever in the “high beam” direction leads to the switching between the automatic and the override mode. Thereby, there is no change in the illuminating state of the headlights.
It is advantageously provided that in the event that the headlights are in the override mode in the first illuminating state, the headlights can be transferred into the second illuminating state by actuating the selector lever in the second actuating direction while retaining the override mode. In this respect, the override mode functions like the manual mode. If, as preferably provided, the first illuminating state corresponds to the high beam, and the second illuminating state corresponds to the low beam, this means that, when the high beam is switched on, an actuation of the selector lever in the “low beam” direction in the override mode leads to a dimming of the lights while simultaneously retaining the override mode. In combination with the prior art override possibility, this means for the driver that in any situation, independently of whether the system is in manual, automatic or override mode, when the high beam is on, the driver can dim the lights by actuating the selector lever in the “low beam” direction. It is not necessary that the driver knows the current mode.
This parallelism with the manual mode exists in an advantageous further development of the invention for the reverse switching direction, but not without limitations. Rather, it is provided that in the event that the highlights in the override mode are in the second illuminating state, an actuation of the selector lever in the first actuating direction causes a switching into the automatic mode, if the automatic mode is ready for use. Expressed in terms of the preferred embodiment as an example, where the first illuminating state corresponds to the high beam, and the second illuminating state corresponds to the low beam, this means that, with the low beam on in override mode, an actuation of the selector lever in the “high beam” direction causes a mode switch to the automatic mode. If then following an analysis of the external lighting situation, it is determined that a switch to the high beam is really appropriate, according to the evaluation rules specified in the automatic mode, a switch is made to the high beam as an automatic process. The switch is not made if the automatic mechanism deems that it is inappropriate to switch to the high beam. However, if, contrary to the analysis of the automatic mechanism, the driver wants to put on the high beams, he can do this by actuating the selector lever again in the high beam direction, a maneuver that leads to a switching from the automatic low beam to the high beam in the override mode. This embodiment is especially advantageous, since experience has taught that a manual switch from low beam to high beam takes place only if there are no other road users in the vicinity who could be endangered by the glare. In this situation, however, it is appropriate not only to put on the high beams, but at the same time to entrust the automatic mechanism again with the control of the headlights.
In this respect it is provided advantageously that in the event that the automatic mode is not ready for use, an actuation of the selector lever in the first actuating direction causes a transfer of the headlights into the first illuminating state while retaining the override mode. With respect to the example described above, this means that in the event that the automatic mechanism is not ready for use, the high beam is switched on directly, as in the manual mode.
Since not every driver appreciates the advantages of an automatic headlight control, it is provided in an advantageous manner that a choice can be made between the manual mode, on the one hand, and the automatic and override mode, on the other hand, by way of a switch. This switch is preferably the main lighting switch, which is typically provided in motor vehicles, and which can be expanded to include another “automatic” position. Therefore, the driver may switch at any time into a purely manual mode and actuate the selector lever in the accustomed manner for controlling the headlights.
Preferably, after switching off the ignition of the motor vehicle, the manual mode is selected automatically. If a vehicle is not taking part in moving traffic, a dynamic adjustment of the headlight control, as provided by the automatic and/or override mode, is not necessary.
As explained above, it is not necessary in an advantageous embodiment of the invention that the driver know explicitly the current mode. Nevertheless, there is a control light that indicates to the driver that the automatic mode is switched on. Especially in the case of drivers who are not familiar with such systems, the automatic switching can otherwise come as a surprise and can therefore be perceived to be unpleasant.
Finally, in the event that the headlights are in the second illuminating state, an actuation of the selector lever in the first actuating direction causes the highlights to brighten for the duration of the actuation. This corresponds to the typical headlight flasher function.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.